1. Field of Invention
The invention relates to the field of fiber optic components, and more particularly to photonic processors.
2. Description of Related Art
Fiber optic communication systems are becoming increasingly popular for data transmission due to their high speed and high data capacity capabilities. Wavelength division multiplexing is used in such fiber optic communication systems to transfer a relatively large amount of data at a high speed. In wavelength division multiplexing, multiple information-carrying signals, each signal having light of a specific restricted wavelength range, may be transmitted along the same optical fiber.
Each individual information-carrying light is referred to as either a xe2x80x9csignalxe2x80x9d or a xe2x80x9cchannelxe2x80x9d. The totality of multiple combined signals in a wavelength-division multiplexed optical fiber, optical line, or optical system, where each signal is of a different wavelength range, is referred to as a xe2x80x9ccomposite optical signalxe2x80x9d.
Due to the rising demand for higher capacity fiber optic systems, physical problems such as chromatic dispersion have conventionally been resolved or alleviated with optical devices such as Gires-Tournois interferometer (GT cavity) dispersion compensators. Moreover, the devices may be cascaded to increase the bandwidth. However, device cascading results in less compact designs while raising the cost of the designs with increasing cascaded devices.
Accordingly, there is a need to reduce the number of devices in a cascaded configuration while maintaining the present bandwidth.
The present invention provides the method and apparatus for multi-pass photonic processors with the use of circulators and multiple-fiber collimators. In one embodiment of the present invention, a circulator is placed at one end and a reflective element at the other end of cascaded photonic processors. The circulator first directs the light signal into a first end of cascaded chain of processors where the signal is processed by all processors in the cascaded chain of processors; a reflective element at a second end of cascaded chain of processors subsequently redirects the light signal back into the cascaded chain of processors to be processed for a second time; the light signal then exits the chain via the circulator. In another embodiment of the present invention, multiple fiber strand pairs are connected to the collimator of a photonic processor. The light signal enters the photonic processor via the first fiber of a first fiber strand pair; the processor then processes the signal and reflects the signal with a reflective element in the GT cavity. The signal is then rerouted and reprocessed for as many times as the number of remaining fiber strand pairs and finally exits the processor via the second fiber strand of the last fiber pair.